Bring vfs.ufs.dirhash_maxmem into the age of the fruitbat and make it autotuned. It is only an upper bound (the memory is not always allocated) and the system contains a vm_lowmem handler so nothing will crash and burn if it's tuned too high.
Bring vfs.ufs.dirhash_maxmem into the age of the fruitbat and make it
autotuned. It is only an upper bound (the memory is not always allocated)
and the system contains a vm_lowmem handler so nothing will crash and burn
if it's tuned too high.

Reviewed by:	mckusick

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase